In recent years, liquid chromatography is often used as a sample analysis method in the field of organic chemistry, biochemistry and medicine. In e.g. a blood test using such a liquid chromatography device, blood collected in a cylindrical blood collection tube is used as a sample. However, blood, if left as it is, separates into blood plasma and blood cells, which leads to incorrect test results. Thus, some liquid chromatography devices are provided with a sample stirring device for stirring blood collected in a blood collection tube. FIG. 21 shows an example of conventional sample stirring device (see Patent Document 1, for example). The illustrated sample stirring device X includes a plurality of rollers 91. Any one of these rollers 91 is driven by a motor, not shown. A blood collection tube C containing blood is held upright in e.g. a stand Y, with a cap Cp attached to it. The blood collection tube C is set between the rollers 91. When the motor starts driving, the rollers 91 and the blood collection tube C start to rotate. Thus, blood in the blood collection tube C is stirred. After the stirring, e.g. a needle-like nozzle (now shown) breaks through the cap Cp to dip the end of the nozzle in the blood. The blood is drawn up through the nozzle and tested as a sample by the liquid chromatography device.
With this arrangement, however, in performing stirring with respect to the blood collection tube C, the blood collection tube C may move in the axial direction relative to the rollers 91. Conceivably, this is because the side surface of the blood collection tube C is not necessarily perpendicular to the rollers 91, which are held horizontally. For instance, when the blood collection tube C is slightly tapered with the dimension in cross section gradually reducing toward the end, the blood collection tube C tends to move upward. Further, a bar-code label for identification is usually attached to the blood collection tube C. When the rollers 91 rotate in contact with the bar-code label or the bar-code label comes into contact with a structural part of the sample stirring device X during rotation, the bar-code label may peel off, which may cause a further problem of hindrance of proper rotation of the blood collection tube C.
The blood collection tube C is held upright in a rack Y, for example. For holding the blood collection tube C upright in the rack Y, some portions of the rack Y need to be in contact with the blood collection tube C. For stable holding of the blood collection tube C, it is desirable that the rack comes into contact with an upper portion of the blood collection tube C. However, the bar-code label for identification is usually attached to an upper portion of the blood collection tube C, so that the bar-code label may be damaged or peeled by the rack Y.    Patent Document 1: JP-A-H07-55815